1. Field of the Invention
The present invention relates to a power apparatus, and particularly to a power apparatus comprising a plurality of interconnected identifiable components defining a network. The present invention also relates to a method of locating a fault or other abnormality (hereinafter referred to generally as a "fault") in such a power apparatus.
2. Summary of the Prior Art
It is known to form a power apparatus by supporting one or more high voltage conductors in a casing of e.g. a metal, and filling that casing with insulating gas. The gas may be, for example, SF.sub.6. Such a power apparatus is used, for example, in a power sub-station for electricity transmission.
The casing forms a network, and within this network it is possible to identify a plurality of interconnected components. The network will have a large number of relatively straight casing sections, but will also normally have insulation spacers, T-junctions, disconnecting switches, circuit breakers and other items of the power apparatus which are necessary for its function. Of course, since the components form a network, the separation of the identifiable components discussed above may not correspond to physical divisions, since, e.g., a T-junction may be integrally connected to the straight sections of the casing leading from the junction, but nevertheless such a T-junction is identifiable as such, and thus the components are identifiable within the network.
Although great care is taken in the construction of such a power apparatus, it is possible for an abnormality to occur in the insulation within the apparatus, and insulation breakdown could lead to a serious accident. Therefore, it is necessary to identify the site of a potential breakdown as early as possible, and with high precision.
When a fault begins to develop in the insulation in such a network, sound waves are generated, and it is possible to arrange a plurality of sound detectors within the network, to detect the sounds generated by a fault. An example of such an arrangement was disclosed in the article entitled "Development of Compact 500 kV 8000A Gas Insulated Transmission Line-Dust Control During Field Jointing and Method for Detecting Conductive Particles" by K. Kaminaga et al in Paper 87 WM003-7 from the IEEE.
It is also known that a fault developing in such a network generates vibration waves, and again it is possible to provide vibration detectors to detect these waves.
Finally, it is known that the development of a fault generates electromagnetic waves, and JP-A-1-287475 and equivalents thereof disclosed the use of such electromagnetic waves for fault location.